jshn: add support for namespaces

Can be used to fix variable namespace clashes in library code using jshn

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

1 files changed, 154 insertions, 49 deletions

diff --git a/sh/jshn.sh b/sh/jshn.sh
index 0f209d3..242e5a4 100644
--- a/sh/jshn.sh
+++ b/sh/jshn.sh
@@ -1,85 +1,184 @@
 # functions for parsing and generating json
 
-jshn_append() {
-	local var="$1"
-	local value="$2"
-	local sep="${3:- }"
+_json_get_var() {
+	local ___dest="$1"
+	local ___var="$2"
+	eval "$___dest=\"\$${JSON_PREFIX}$___var\""
+}
 
-	eval "export -- \"$var=\${$var:+\${$var}\${value:+\$sep}}\$value\""
+_json_set_var() {
+	local ___var="$1"
+	local ___val="$2"
+	eval "${JSON_PREFIX}$___var=\"\$___val\""
 }
 
-json_init() {
-	[ -n "$JSON_UNSET" ] && eval "unset $JSON_UNSET"
-	export -- JSON_SEQ=0 JSON_STACK= JSON_CUR="JSON_VAR" JSON_UNSET="" KEYS_JSON_VAR= TYPE_JSON_VAR=
+_jshn_append() {
+	local __var="$1"
+	local __value="$2"
+	local __sep="${3:- }"
+	local __old_val
+
+	_json_get_var __old_val "$__var"
+	__value="${__old_val:+$__old_val$__sep}$__value"
+	_json_set_var "$__var" "$__value"
+}
+
+_json_export() {
+	local __var="${JSON_PREFIX}$1"
+	local __val="$2"
+
+	export -- "$__var=$__val"
+	_jshn_append "JSON_UNSET" "$__var"
+}
+
+_json_add_key() {
+	local table="$1"
+	local var="$2"
+	_jshn_append "KEYS_${table}" "$var"
+}
+
+_get_var() {
+	local __dest="$1"
+	local __var="$2"
+	eval "$__dest=\"\$$__var\""
+}
+
+_set_var() {
+	local __var="$1"
+	local __val="$2"
+	eval "$__var=\"\$__val\""
+}
+
+_json_inc() {
+	local _var="$1"
+	local _dest="$2"
+	local seq
+
+	_json_get_var seq "$_var"
+	seq="$((${seq:-0} + 1))"
+	_json_set_var "$_var" "$seq"
+	[ -n "$dest" ] && _set_var "$_dest" "$seq"
 }
 
-json_add_generic() {
+_json_stack_push() {
+	local new_cur="$1"
+	local cur
+
+	_json_get_var cur JSON_CUR
+	_jshn_append JSON_STACK "$cur"
+	_json_set_var JSON_CUR "$new_cur"
+}
+
+_json_add_generic() {
 	local type="$1"
 	local var="$2"
 	local val="$3"
-	local cur="${4:-$JSON_CUR}"
+	local cur="$4"
+
+	[ -n "$cur" ] || _json_get_var cur JSON_CUR
 
 	if [ "${cur%%[0-9]*}" = "JSON_ARRAY" ]; then
-		eval "local aseq=\"\${SEQ_$cur}\""
-		var=$(( ${aseq:-0} + 1 ))
-		export -- "SEQ_$cur=$var"
+		_json_inc "SEQ_$cur" var
 	else
 		local name="${var//[^a-zA-Z0-9_]/_}"
-		[[ "$name" == "$var" ]] || export -- "NAME_${cur}_${name}=$var"
+		[[ "$name" == "$var" ]] || _json_export "NAME_${cur}_${name}" "$var"
 		var="$name"
 	fi
 
-	export -- "${cur}_$var=$val"
-	export -- "TYPE_${cur}_$var=$type"
-	jshn_append JSON_UNSET "${cur}_$var TYPE_${cur}_$var"
-	jshn_append "KEYS_${cur}" "$var"
+	_json_export "${cur}_$var" "$val"
+	_json_export "TYPE_${cur}_$var" "$type"
+	_json_add_key "$cur" "$var"
 }
 
-json_add_table() {
-	local TYPE="$1"
-	JSON_SEQ=$(($JSON_SEQ + 1))
-	jshn_append JSON_STACK "$JSON_CUR"
-	local table="JSON_$TYPE$JSON_SEQ"
-	export -- "UP_$table=$JSON_CUR"
-	export -- "KEYS_$table="
-	jshn_append JSON_UNSET "KEYS_$table UP_$table"
-	[ "$TYPE" = "ARRAY" ] && jshn_append JSON_UNSET "SEQ_$table"
-	JSON_CUR="$table"
+_json_add_table() {
+	local name="$1"
+	local type="$2"
+	local itype="$3"
+	local cur new_cur
+
+	_json_get_var cur JSON_CUR
+	_json_inc JSON_SEQ seq
+
+	local table="JSON_$itype$seq"
+	_json_export "UP_$table" "$cur"
+	_json_export "KEYS_$table" ""
+	[ "$TYPE" = "ARRAY" ] && _json_export "KEYS_$table" ""
+	_json_stack_push "$table"
+
+	_json_get_var new_cur JSON_CUR
+	_json_add_generic object "$1" "$new_cur" "$cur"
+}
+
+_json_close_table() {
+	local stack new_stack
+
+	_json_get_var stack JSON_STACK
+	_json_set_var cur "${JSON_STACK##* }"
+	new_stack="${stack% *}"
+	[[ "$stack" == "$new_stack" ]] && new_stack=
+	_json_set_var JSON_STACK "$new_stack"
+}
+
+json_set_namespace() {
+	local _new="$1"
+	local _old="$2"
+
+	[ -n "$_old" ] && _set_var "$_old" "$JSON_PREFIX"
+	JSON_PREFIX="$_new"
+}
+
+json_cleanup() {
+	local unset
+
+	_json_get_var unset JSON_UNSET
+	[ -n "$unset" ] && eval "unset $unset"
+
+	unset \
+		${JSON_PREFIX}JSON_SEQ \
+		${JSON_PREFIX}JSON_STACK \
+		${JSON_PREFIX}JSON_CUR \
+		${JSON_PREFIX}JSON_UNSET \
+		${JSON_PREFIX}KEYS_JSON_VAR \
+		${JSON_PREFIX}TYPE_JSON_VAR
+}
+
+json_init() {
+	json_cleanup
+	export -- \
+		${JSON_PREFIX}JSON_SEQ=0 \
+		${JSON_PREFIX}JSON_STACK= \
+		${JSON_PREFIX}JSON_CUR="JSON_VAR" \
+		${JSON_PREFIX}JSON_UNSET="" \
+		${JSON_PREFIX}KEYS_JSON_VAR= \
+		${JSON_PREFIX}TYPE_JSON_VAR=
 }
 
 json_add_object() {
-	local cur="$JSON_CUR"
-	json_add_table TABLE
-	json_add_generic object "$1" "$JSON_CUR" "$cur"
+	_json_add_table "$1" object TABLE
 }
 
 json_close_object() {
-	local oldstack="$JSON_STACK"
-	JSON_CUR="${JSON_STACK##* }"
-	JSON_STACK="${JSON_STACK% *}"
-	[[ "$oldstack" == "$JSON_STACK" ]] && JSON_STACK=
+	_json_close_table
 }
 
 json_add_array() {
-	local cur="$JSON_CUR"
-	json_add_table ARRAY
-	json_add_generic array "$1" "$JSON_CUR" "$cur"
+	_json_add_table "$1" array ARRAY 
 }
 
 json_close_array() {
-	json_close_object
+	_json_close_table
 }
 
 json_add_string() {
-	json_add_generic string "$1" "$2"
+	_json_add_generic string "$1" "$2"
 }
 
 json_add_int() {
-	json_add_generic int "$1" "$2"
+	_json_add_generic int "$1" "$2"
 }
 
 json_add_boolean() {
-	json_add_generic boolean "$1" "$2"
+	_json_add_generic boolean "$1" "$2"
 }
 
 # functions read access to json variables
@@ -89,19 +188,25 @@ json_load() {
 }
 
 json_dump() {
-	jshn "$@" -w
+	jshn "$@" ${JSON_PREFIX:+-p "$JSON_PREFIX"} -w 
 }
 
 json_get_type() {
 	local dest="$1"
-	local var="TYPE_${JSON_CUR}_$2"
+	local cur
+
+	_json_get_var cur JSON_CUR
+	local var="${JSON_PREFIX}TYPE_${cur}_$2"
 	eval "export -- \"$dest=\${$var}\"; [ -n \"\${$var+x}\" ]"
 }
 
 json_get_var() {
-	local dest="$1"
-	local var="${JSON_CUR}_${2//[^a-zA-Z0-9_]/_}"
-	eval "export -- \"$dest=\${$var}\"; [ -n \"\${$var+x}\" ]"
+	local __dest="$1"
+	local __cur
+
+	_json_get_var __cur JSON_CUR
+	local __var="${JSON_PREFIX}${__cur}_${2//[^a-zA-Z0-9_]/_}"
+	eval "export -- \"$__dest=\${$__var}\"; [ -n \"\${$__var+x}\" ]"
 }
 
 json_get_vars() {
@@ -116,7 +221,7 @@ json_select() {
 	local type
 
 	[ -z "$1" ] && {
-		JSON_CUR="JSON_VAR"
+		_json_set_var JSON_CUR "JSON_VAR"
 		return 0
 	}
 	[[ "$1" == ".." ]] && {
@@ -126,7 +231,7 @@ json_select() {
 	json_get_type type "$target"
 	case "$type" in
 		object|array)
-			json_get_var JSON_CUR "$target"
+			_json_get_var JSON_CUR "$target"
 		;;
 		*)
 			echo "WARNING: Variable '$target' does not exist or is not an array/object"